linux-toradex.git/Documentation/bpf, branch v6.7

bpf: Add __bpf_kfunc_{start,end}_defs macros

2023-11-02T05:33:53+00:00

BPF kfuncs are meant to be called from BPF programs. Accordingly, most
kfuncs are not called from anywhere in the kernel, which the
-Wmissing-prototypes warning is unhappy about. We've peppered
__diag_ignore_all("-Wmissing-prototypes", ... everywhere kfuncs are
defined in the codebase to suppress this warning.

This patch adds two macros meant to bound one or many kfunc definitions.
All existing kfunc definitions which use these __diag calls to suppress
-Wmissing-prototypes are migrated to use the newly-introduced macros.
A new __diag_ignore_all - for "-Wmissing-declarations" - is added to the
__bpf_kfunc_start_defs macro based on feedback from Andrii on an earlier
version of this patch [0] and another recent mailing list thread [1].

In the future we might need to ignore different warnings or do other
kfunc-specific things. This change will make it easier to make such
modifications for all kfunc defs.

  [0]: https://lore.kernel.org/bpf/CAEf4BzaE5dRWtK6RPLnjTW-MW9sx9K3Fn6uwqCTChK2Dcb1Xig@mail.gmail.com/
  [1]: https://lore.kernel.org/bpf/ZT+2qCc%2FaXep0%2FLf@krava/

Signed-off-by: Dave Marchevsky 
Suggested-by: Andrii Nakryiko 
Acked-by: Andrii Nakryiko 
Cc: Jiri Olsa 
Acked-by: Jiri Olsa 
Acked-by: David Vernet 
Acked-by: Yafang Shao 
Link: https://lore.kernel.org/r/20231031215625.2343848-1-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov

bpf, docs: Define signed modulo as using truncated division

2023-10-18T23:36:12+00:00

There's different mathematical definitions (truncated, floored, rounded,
etc.) and different languages have chosen different definitions [0][1].
E.g., languages/libraries that follow Knuth use a different mathematical
definition than C uses. This patch specifies which definition BPF uses,
as verified by Eduard [2] and others.

  [0] https://en.wikipedia.org/wiki/Modulo#Variants_of_the_definition
  [1] https://torstencurdt.com/tech/posts/modulo-of-negative-numbers/
  [2] https://lore.kernel.org/bpf/57e6fefadaf3b2995bb259fa8e711c7220ce5290.camel@gmail.com/

Signed-off-by: Dave Thaler 
Signed-off-by: Daniel Borkmann 
Acked-by: David Vernet 
Acked-by: Eduard Zingerman 
Link: https://lore.kernel.org/bpf/20231017203020.1500-1-dthaler1968@googlemail.com

documentation/bpf: Document cgroup unix socket address hooks

2023-10-12T00:27:55+00:00

Update the documentation to mention the new cgroup unix sockaddr
hooks.

Signed-off-by: Daan De Meyer 
Link: https://lore.kernel.org/r/20231011185113.140426-8-daan.j.demeyer@gmail.com
Signed-off-by: Martin KaFai Lau

docs/bpf: update out-of-date doc in BPF flow dissector

2023-09-13T21:22:57+00:00

Commit a5e2151ff9d5 ("net/ipv6: SKB symmetric hash should incorporate
transport ports") removed the use of FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL
in __skb_get_hash_symmetric(), making the doc out-of-date.

Signed-off-by: Quan Tian 
Link: https://lore.kernel.org/r/20230911152353.8280-1-qtian@vmware.com
Signed-off-by: Martin KaFai Lau

Merge tag 'net-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2023-09-08T01:33:07+00:00

Pull networking updates from Jakub Kicinski:
 "Including fixes from netfilter and bpf.

  Current release - regressions:

   - eth: stmmac: fix failure to probe without MAC interface specified

  Current release - new code bugs:

   - docs: netlink: fix missing classic_netlink doc reference

  Previous releases - regressions:

   - deal with integer overflows in kmalloc_reserve()

   - use sk_forward_alloc_get() in sk_get_meminfo()

   - bpf_sk_storage: fix the missing uncharge in sk_omem_alloc

   - fib: avoid warn splat in flow dissector after packet mangling

   - skb_segment: call zero copy functions before using skbuff frags

   - eth: sfc: check for zero length in EF10 RX prefix

  Previous releases - always broken:

   - af_unix: fix msg_controllen test in scm_pidfd_recv() for
     MSG_CMSG_COMPAT

   - xsk: fix xsk_build_skb() dereferencing possible ERR_PTR()

   - netfilter:
      - nft_exthdr: fix non-linear header modification
      - xt_u32, xt_sctp: validate user space input
      - nftables: exthdr: fix 4-byte stack OOB write
      - nfnetlink_osf: avoid OOB read
      - one more fix for the garbage collection work from last release

   - igmp: limit igmpv3_newpack() packet size to IP_MAX_MTU

   - bpf, sockmap: fix preempt_rt splat when using raw_spin_lock_t

   - handshake: fix null-deref in handshake_nl_done_doit()

   - ip: ignore dst hint for multipath routes to ensure packets are
     hashed across the nexthops

   - phy: micrel:
      - correct bit assignments for cable test errata
      - disable EEE according to the KSZ9477 errata

  Misc:

   - docs/bpf: document compile-once-run-everywhere (CO-RE) relocations

   - Revert "net: macsec: preserve ingress frame ordering", it appears
     to have been developed against an older kernel, problem doesn't
     exist upstream"

* tag 'net-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (95 commits)
  net: enetc: distinguish error from valid pointers in enetc_fixup_clear_rss_rfs()
  Revert "net: team: do not use dynamic lockdep key"
  net: hns3: remove GSO partial feature bit
  net: hns3: fix the port information display when sfp is absent
  net: hns3: fix invalid mutex between tc qdisc and dcb ets command issue
  net: hns3: fix debugfs concurrency issue between kfree buffer and read
  net: hns3: fix byte order conversion issue in hclge_dbg_fd_tcam_read()
  net: hns3: Support query tx timeout threshold by debugfs
  net: hns3: fix tx timeout issue
  net: phy: Provide Module 4 KSZ9477 errata (DS80000754C)
  netfilter: nf_tables: Unbreak audit log reset
  netfilter: ipset: add the missing IP_SET_HASH_WITH_NET0 macro for ip_set_hash_netportnet.c
  netfilter: nft_set_rbtree: skip sync GC for new elements in this transaction
  netfilter: nf_tables: uapi: Describe NFTA_RULE_CHAIN_ID
  netfilter: nfnetlink_osf: avoid OOB read
  netfilter: nftables: exthdr: fix 4-byte stack OOB write
  selftests/bpf: Check bpf_sk_storage has uncharged sk_omem_alloc
  bpf: bpf_sk_storage: Fix the missing uncharge in sk_omem_alloc
  bpf: bpf_sk_storage: Fix invalid wait context lockdep report
  s390/bpf: Pass through tail call counter in trampolines
  ...

docs/bpf: Fix "file doesn't exist" warnings in {llvm_reloc,btf}.rst

2023-09-01T13:56:48+00:00

scripts/documentation-file-ref-check reports warnings for (valid) cross-links
of form:

  :ref:`Documentation/bpf/btf `

Adding extension to the file name helps to avoid the warning, e.g:

  :ref:`Documentation/bpf/btf.rst `

Fixes: be4033d36070 ("docs/bpf: Add description for CO-RE relocations")
Reported-by: kernel test robot 
Signed-off-by: Eduard Zingerman 
Signed-off-by: Daniel Borkmann 
Acked-by: Jiri Olsa 
Closes: https://lore.kernel.org/oe-kbuild-all/202309010804.G3MpXo59-lkp@intel.com
Link: https://lore.kernel.org/bpf/20230901125935.487972-1-eddyz87@gmail.com

Merge tag 'docs-6.6' of git://git.lwn.net/linux

2023-08-31T03:05:42+00:00

Pull documentation updates from Jonathan Corbet:
 "Documentation work keeps chugging along; this includes:

   - Work from Carlos Bilbao to integrate rustdoc output into the
     generated HTML documentation. This took some work to figure out how
     to do it without slowing the docs build and without creating people
     who don't have Rust installed, but Carlos got there

   - Move the loongarch and mips architecture documentation under
     Documentation/arch/

   - Some more maintainer documentation from Jakub

  ... plus the usual assortment of updates, translations, and fixes"

* tag 'docs-6.6' of git://git.lwn.net/linux: (56 commits)
  Docu: genericirq.rst: fix irq-example
  input: docs: pxrc: remove reference to phoenix-sim
  Documentation: serial-console: Fix literal block marker
  docs/mm: remove references to hmm_mirror ops and clean typos
  docs/zh_CN: correct regi_chg(),regi_add() to region_chg(),region_add()
  Documentation: Fix typos
  Documentation/ABI: Fix typos
  scripts: kernel-doc: fix macro handling in enums
  scripts: kernel-doc: parse DEFINE_DMA_UNMAP_[ADDR|LEN]
  Documentation: riscv: Update boot image header since EFI stub is supported
  Documentation: riscv: Add early boot document
  Documentation: arm: Add bootargs to the table of added DT parameters
  docs: kernel-parameters: Refer to the correct bitmap function
  doc: update params of memhp_default_state=
  docs: Add book to process/kernel-docs.rst
  docs: sparse: fix invalid link addresses
  docs: vfs: clean up after the iterate() removal
  docs: Add a section on surveys to the researcher guidelines
  docs: move mips under arch
  docs: move loongarch under arch
  ...

bpf, docs: s/eBPF/BPF in standards documents

2023-08-30T14:36:10+00:00

There isn't really anything other than just "BPF" at this point,
so referring to it as "eBPF" in our standards document just causes
unnecessary confusion. Let's just be consistent and use "BPF".

Suggested-by: Will Hawkins 
Signed-off-by: David Vernet 
Signed-off-by: Daniel Borkmann 
Link: https://lore.kernel.org/bpf/20230828155948.123405-4-void@manifault.com

bpf, docs: Add abi.rst document to standardization subdirectory

2023-08-30T14:35:58+00:00

As specified in the IETF BPF charter, the BPF working group has plans to
add one or more informational documents that recommend conventions and
guidelines for producing portable BPF program binaries. The
instruction-set.rst document currently contains a "Registers and calling
convention" subsection which dictates a calling convention that belongs
in an ABI document, rather than an instruction set document. Let's move
it to a new abi.rst document so we can clean it up. The abi.rst document
will of course be significantly changed and expanded upon over time. For
now, it's really just a placeholder which will contain ABI-specific
language that doesn't belong in other documents.

Signed-off-by: David Vernet 
Signed-off-by: Daniel Borkmann 
Link: https://lore.kernel.org/bpf/20230828155948.123405-3-void@manifault.com

bpf, docs: Move linux-notes.rst to root bpf docs tree

2023-08-30T14:35:44+00:00

In commit 4d496be9ca05 ("bpf,docs: Create new standardization
subdirectory"), I added a standardization/ directory to the BPF
documentation, which will contain the docs that will be standardized
as part of the effort with the IETF.

I included linux-notes.rst in that directory, but I shouldn't have. It
doesn't contain anything that will be standardized. Let's move it back
to Documentation/bpf.

Signed-off-by: David Vernet 
Signed-off-by: Daniel Borkmann 
Link: https://lore.kernel.org/bpf/20230828155948.123405-2-void@manifault.com